A typical retractable tape rule assembly includes an elongated thin metal rule blade that is mounted on a reel rotatably disposed within a housing assembly. The rule blade is retracted into the housing assembly for storage by coiling it about the reel. A coil spring is mounted between the reel and housing assembly to provide spring powered rewinding of the blade about the reel to the fully retracted position of the blade after the measurement has been taken. Repeatedly extension and retraction is stressful on the blade, however. It has been found that the first several inches of the free end of the blade are particularly susceptible to damage and wear over the life of the tape assembly. The leading end of the blade is frequently handled, for example, by the tape assembly user to pull the tape out of the housing assembly or to hold the free end of the tape on the workpiece. This repeated handling of the free end of the tape exposes the numbering and graduation lines on the face of the tape to wear and over time can wear these markings off. Spring powered retraction of the blade may cause fairly rapid rewinding of the blade into the housing assembly, causing the last several inches of the rewinding tape (i.e., the several inches on the free end of the tape) to "whip" or hit against the portions of the housing assembly that define the housing assembly opening. Over time, this hitting action of the tape against the housing assembly opening leads to cracks or tears in the tape and eventual tape breakage. Most breaks in the tapes of tape assemblies in commercial use occur in the first six inches of the blade.
Although tape wear and breakage could be reduced by increasing the thickness of the metal of the blade, this is undesirable for several reasons. A thick blade increases tape assembly size, weight and material cost. A uniformly thick blade may have a detrimental effect on blade standout by increasing the weight of the extended portion of the blade. Furthermore, experience has shown that thickening or reinforcement of the entire blade length is not necessary to maximize service life of a rule assembly because most breaks and most blade wear occur in the several leading inches of the blade.
A need exists for a low cost, lightweight, durable material to cover and reinforce a selected length of a retractable tape blade that is easy to apply, highly durable and that can be used on any known tape rule product.